https://github.com/lambdalisue/deno-unnullish

🦕 An opposite function of nullish coalescing operator
https://github.com/lambdalisue/deno-unnullish

deno jsr nullish

Last synced: 12 days ago
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🦕 An opposite function of nullish coalescing operator

• Host: GitHub
• URL: https://github.com/lambdalisue/deno-unnullish
• Owner: lambdalisue
• License: mit
• Created: 2022-08-05T02:28:39.000Z (about 2 years ago)
• Default Branch: main
• Last Pushed: 2024-04-06T08:29:40.000Z (7 months ago)
• Last Synced: 2024-10-04T15:31:55.886Z (about 1 month ago)
• Topics: deno, jsr, nullish
• Language: TypeScript
• Homepage: https://jsr.io/@lambdalisue/unnullish
• Size: 18.6 KB
• Stars: 15
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# unnullish

[![jsr](https://img.shields.io/jsr/v/%40lambdalisue/unnullish?logo=javascript&logoColor=white)](https://jsr.io/@lambdalisue/unnullish)

[![denoland](https://img.shields.io/github/v/release/lambdalisue/deno-unnullish?logo=deno&label=denoland)](https://github.com/lambdalisue/deno-unnullish/releases)

[![npm](http://img.shields.io/badge/available%20on-npm-lightgrey.svg?logo=npm&logoColor=white)](https://www.npmjs.com/package/unnullish)

[![deno doc](https://doc.deno.land/badge.svg)](https://doc.deno.land/https/deno.land/x/unnullish/mod.ts)

[![Test](https://github.com/lambdalisue/deno-unnullish/workflows/Test/badge.svg)](https://github.com/lambdalisue/deno-unnullish/actions?query=workflow%3ATest)

[![npm version](https://badge.fury.io/js/unnullish.svg)](https://badge.fury.io/js/unnullish)

`unnullish` returns `undefined` if `value` is nullish, otherwise it executes

`callback` and returns the result. It is an opposite function of the

[nullish coalescing operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing_operator)

(`??`).

[nullish coalescing operator]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing_operator

## Usage

### unnullish

- `unnullish(value: T | null | undefined, callback(v: T) => R): R | undefined`

The function is useful when you want to apply some transformation functions to

optional values. For example,

```typescript

import { unnullish } from "https://deno.land/x/unnullish@$MODULE_VERSION/mod.ts";

type Options = {

  foo?: string;

  bar?: number;

};

function sayHello(v: string): string {

  return `Hello ${v}`;

}

const options: Options = {

  foo: unnullish(Deno.env.get("foo"), (v) => sayHello(v)),

  // instead of

  //foo: Deno.env.get("foo") != null

  //  ? sayHello(Deno.env.get("foo"))

  //  : undefined,

  bar: unnullish(Deno.env.get("bar"), (v) => parseInt(v, 10)),

  // instead of

  //bar: Deno.env.get("bar") != null

  //  ? parseInt(Deno.env.get("bar"), 10)

  //  : undefined,

};

```

Note that the function returns `undefined` even the input is `null`, mean that

you may need to use nullish coalescing operator to normalize the result. For

example,

```typescript

import { unnullish } from "https://deno.land/x/unnullish@$MODULE_VERSION/mod.ts";

console.log(unnullish(null, () => 0));

// -> undefined

console.log(unnullish(undefined, () => 0));

// -> undefined

console.log(unnullish(null, () => 0) ?? null);

// -> null

console.log(unnullish(undefined, () => 0) ?? null);

// -> null

```

## License

The code follows MIT license written in [LICENSE](./LICENSE). Contributors need

to agree that any modifications sent in this repository follow the license.